Some users of Reader 10.1.2 are having an issue with crashing when printing. Please see this thread for help with the issue: http://forums.adobe.com/thread/949886?tstart=0

Adobe Reader is not fully compatibile with OS X.7 from http://kb2.adobe.com/cps/908/cpsid_90885.html

Overview

Adobe Reader plug-in and Acrobat plug-in are not compatible with the Safari 5.1 browser, which will ship with Mac OS X 10.7 and for 10.6 in July. Adobe Reader and Acrobat will continue to work as standalone applications on Mac OS X 10.7 and 10.6, and will render PDF documents outside of the browser. In addition, Safari 5.1 renders PDF documents natively. However, the Adobe Reader and Acrobat plug-ins will not function as expected in LiveCycle and Acrobat workflows that require either plug-in to render PDF documents in Safari 5.1.

Affected Customers

Applications that require the Adobe Reader or Acrobat plug-in to render PDF documents in the Safari browser will be affected. For Adobe Reader, Acrobat, and LiveCycle customers who utilize functionality like forms, digital signatures, portfolios, guides, 3D, extended PDFs and rights management, and who require the Adobe Reader or Acrobat plug-in to render PDF documents in the Safari browser, Adobe recommends that you continue to use Safari 5.0.x and Mac OS X 10.6. 

Workarounds

Adobe Reader and Acrobat will still work as expected outside of the browser. For cases in which a user can open a PDF document in Safari, but cannot use all of the functionality in the PDF because it requires Adobe Reader or Acrobat, the user can save the PDF file from Safari to his or her computer, and then open it directly in Adobe Reader or Acrobat.

In other cases, such as Adobe Reader, Acrobat and LiveCycle applications that utilize functionality like forms, digital signatures, portfolios, guides, 3D, extended PDFs and rights management, viewing a PDF inside the browser with the Adobe Reader or Acrobat plug-in may be required, and thus this workaround will not be successful.